Method of and apparatus for cleaning pulp-screens.



J. BISHOP.

METHOD OF AND APPARATUS FOR CLEANING PULPv SCREENS.

APPLICATION FILED MAR. 15. 1915.

3 ,25; Patefited'July 20,1915.

JAMES BISHOP, OF CARTHAGE, NEW YORK.

METHOD OF AND APPARATUS FOR CLEANING PULP-SCREENS.

citizen of the United States of America, anda resident of Carthage, county of Jefferson,

'State of New York, have invented certain new and useful Improvements in Methods of and Apparatus for Cleaning Pulp- Screens, of which the following is a full and clear specification, reference being had to the accompanying drawings, in which Figure 1 is a vertical sectional view showing my device in operation upon a screen charged with pulp; and Fig. 2 a perspective view of my apparatus.

In many paper mills it is customary in cleaning pulp screens to knock or, pound the screens to loosen the slivers and coarse stulf lodged in the slits and in other mills it is customary to dislodge the slivers and coarse stuff by forcing them downwardly out of the slits by means of jets of steam or water. These methods are objectionable in that the first one results in injury to the plates and the second one in waste of pulp, since the slivers and coarse stuff are carried down into the screened pulp and thus render the batch dirty and inferior, and this requires that it be used, if at all, for an inferior grade of paper.

It is the object of my invention-to provide not only for cleaning the screen without stopping the screening operation, but also without loss or contamination of pulp, as more fully hereinafter set forth.

The apparatus I employ consists of a suc-.

tion nozzle a which is in the form of a long narrow box or chamber having a narrow inlet 7) along its lower straight edge and a central outlet-.0 in its top wall. Connected to the outlet 0 is an aspirator consisting of a suction tube d extending horizontally across the top of the nozzle and having its under side connected to the outlet 0 of the nozzle. The exist end 6 of this suction tube is turned downwardly, and at the other end of this suction tube is inserted the injector tube f of the aspirator, this injector tube 7 extending across the outlet 0. The injector tube f is connected to a flexible pipe or hose g which at its other end is connected to a steam pipe it. A suitable handle a is connected to the nozzle box orchamber to enable'the device to be manipulated. It will be seen that when steam under pressure is admitted to the injector tube 7 it will create a suction up through the nozzle and will Specification of Letters Patent. Papjggnted July 20, 1915,

Application filed March 15, 1915. Serial No. 14,574.

cause a discharge out throughthe downwardly-turned end e of the suction tube.

To-clean a screen with my device, it is obvious that it is simply necessary to admit the steam into the aspirator and then by means of the handle move the nozzle back and forth across the upper surface of the screen, thus causing a suction up through the nozzle throughout the length of its slitlike inlet 72. It will be seen that with a steam pressure sufiiciently high, the suction will be great enough to force out of the slits of the screen all the slivers and coarse stufi' lodged therein. All the water, pulp, slivers, etc, that are drawn up through the nozzle will be deposited back into the pulp on the screen, thereby causing it to be again subjected to a screening action.

When my device is used to clean the screen while the same is in use, the nozzle will be partly immersed in the body ofpulp on the screen, as shown in Fig. 1, and as the nozzle is moved about on the screen, suction around the lower edges of the nozzle ,will cause an accumulation of slivers and coarse stud around said edges, which accumulation will move about with the nozzle and serve to effectually seal the nozzle against entrance of air or pulp' matter from above the screen, thus-compelling the full strength of the suction to take place up through the slits of the screen. In actually using my device in this manner, I have found this sealing efl'ect to be so nearly perfect as to cause the nozzle to be held very tightly against the screen, so tightly in fact that at times it is so difiicult to move along the screen that it is necessary that the vacuum be relieved slightly by tilting the nozzle forwardly or backwardly far enough to raise the rear or the front edge of the nozzle oil thescreen plate.

In using my device on a charged screen, the best results are obtained by beginning 5.00 at one end and pushing the device along the I lot up through the nozzle are all discharged back into the pulp mass, resulting in avoiding all loss of pulp material and also permitting the screen to be cleaned in a cleanly manner.

It will be understood that in the operatio of my apparatus there Will always be su'flg cient water and pulp accumulated on th under side of the screen plate to augment the power of the upgoing air; current in initially dislodging the slivers from the slits, whereby even the most securely lodged slivers and dirt Will be readily and instantly sucked out of the slits. I prefer'employing steani'in the aspirator, not only because that is generally easy to obtain a supply of, but also because a more powerful suction can be obtained With it than With air.

Having thus described my invention, What 1 claim is: I

1. An apparatus for cleaning pulp screens consisting oi' a source of fluid pressure supply, a flexible pipe connected thereto at one end, an aspirator connected to the other end thereof, said aspirator having its discharge tube directed downwardly, a nozzle chamber connected to said aspirator, whereby when the nozzle is moved about on the, screen the matter in the slits of the screen Will be drawn up through the nozzle and discharged back into the pulp mass on the screen.

2. The method herein described for clean seal the joint between its edges and the upper face of the screen.

In testimony whereof ll hereunto ailix my signature 1n the presence of two wltnesses.

JAMES BISHOP. l/Vitnesses W. D. BALL, W. J. HEATH. 

